This invention relates to a holding fixture for impact sound stressing semiconductor materials and, more particularly, the invention is concerned with providing a novel assembly for inserting, clamping and removing the semiconductor material with improved damage distribution as related to reproducible and uniform clamping pressure and membrane mounting. Variations in wafer thickness are compensated for automatically while loss of impact material is minimized.
Heretofore, insertion and removal of the semiconductor wafer into and out of the holding fixture required considerable time and effort to accomplish. Each wafer had to be clamped separately in the fixture and the operator could unload and reload only a single wafer at a time. Many times the damage distribution was not uniform or reproducible because of the uneven clamping pressure and membrane mounting. Compensation for variations of wafer thickness had to be considered when clamping the wafer material prior to impact sound stressing thereof. Also, loss of considerable quantities of impact material would occur during each insertion and removal of the wafer material.
U.S. Pat. Nos. 4,004,449 and 4,018,626 describe the process and use of impact sound stressing.